C# で xlsxファイルを CSV・JSON・XML などに変換する方法: Excelエクスポートガイド

using IronXL;

// Load an existing Excel workbook
WorkBook workbook = WorkBook.Load("Normal_Excel_File.xlsx");

// Set metadata title for the workbook
workbook.Metadata.Title = "Normal_Excel_File.xlsx";

// Save the workbook in different formats
workbook.SaveAs("XLS_Export.xls");
workbook.SaveAs("XLSX_Export.xlsx");
workbook.SaveAsCsv("CSV_Export.csv");
workbook.SaveAsJson("JSON_Export.json");
workbook.SaveAsXml("XML_Export.xml");

// Convert the workbook to a DataSet, allowing integration with other data tools like DataGridView
System.Data.DataSet dataSet = workbook.ToDataSet();

Imports IronXL

' Load an existing Excel workbook
Dim workbook As WorkBook = WorkBook.Load("Normal_Excel_File.xlsx")

' Set metadata title for the workbook
workbook.Metadata.Title = "Normal_Excel_File.xlsx"

' Save the workbook in different formats
workbook.SaveAs("XLS_Export.xls")
workbook.SaveAs("XLSX_Export.xlsx")
workbook.SaveAsCsv("CSV_Export.csv")
workbook.SaveAsJson("JSON_Export.json")
workbook.SaveAsXml("XML_Export.xml")

' Convert the workbook to a DataSet, allowing integration with other data tools like DataGridView
Dim dataSet As System.Data.DataSet = workbook.ToDataSet()

using IronXL;

// Load workbook and select specific worksheet
WorkBook workbook = WorkBook.Load("MultiSheet.xlsx");
WorkSheet sheet = workbook.WorkSheets["SalesData"];

// Convert just one worksheet to CSV with custom delimiter
sheet.SaveAsCsv("SalesData.csv", delimiter: ";");

// Export to JSON with formatting preserved
var jsonOptions = new JsonSaveOptions
{
    PreserveFormatting = true,
    IncludeHeaders = true
};
sheet.SaveAsJson("SalesData.json", jsonOptions);

// Convert to XML with custom root element
sheet.SaveAsXml("SalesData.xml", "SalesReport");

Imports IronXL

' Load workbook and select specific worksheet
Dim workbook As WorkBook = WorkBook.Load("MultiSheet.xlsx")
Dim sheet As WorkSheet = workbook.WorkSheets("SalesData")

' Convert just one worksheet to CSV with custom delimiter
sheet.SaveAsCsv("SalesData.csv", delimiter:=";")

' Export to JSON with formatting preserved
Dim jsonOptions As New JsonSaveOptions With {
    .PreserveFormatting = True,
    .IncludeHeaders = True
}
sheet.SaveAsJson("SalesData.json", jsonOptions)

' Convert to XML with custom root element
sheet.SaveAsXml("SalesData.xml", "SalesReport")

using IronXL;
using System.Threading.Tasks;

// Async conversion for large files
public async Task ConvertLargeFileAsync(string inputPath)
{
    WorkBook workbook = WorkBook.Load(inputPath);

    // Parallel export to multiple formats
    var tasks = new[]
    {
        Task.Run(() => workbook.SaveAsCsv("output.csv")),
        Task.Run(() => workbook.SaveAsJson("output.json")),
        Task.Run(() => workbook.SaveAsXml("output.xml"))
    };

    await Task.WhenAll(tasks);
}

Imports IronXL
Imports System.Threading.Tasks

' Async conversion for large files
Public Async Function ConvertLargeFileAsync(inputPath As String) As Task
    Dim workbook As WorkBook = WorkBook.Load(inputPath)

    ' Parallel export to multiple formats
    Dim tasks = New Task() {
        Task.Run(Sub() workbook.SaveAsCsv("output.csv")),
        Task.Run(Sub() workbook.SaveAsJson("output.json")),
        Task.Run(Sub() workbook.SaveAsXml("output.xml"))
    }

    Await Task.WhenAll(tasks)
End Function